SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df1a7d4607fc236ce575eab58e3b3cdd8a0058b4d37a56de8baee874d028fa4' 
  AND token = 'Iy0s+vtoTV2Wg+2aRuBS7SnRXlOeIdHoSx9/qyLmcu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}