SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1993f8344deb0757c583f0b235c56dc503dd47d9d3f4433364d20726a1859ad4' 
  AND token = 'vICJII7DoNd8a8lU8Z1dqtcLcjeRvKaePPSrDOje12g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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