SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac67a3eeed81a5e804fa7b1eff89f84de35068380467891f585f0930ee478cc7' 
  AND token = '1pA7Xt0UqLUHpWeXBFO/wzAnPxlI+d5Mv3m8LIDYxrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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