SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0008bd82a09937a1f8140b3192d5ba87948d93951ef2c42fcf9804d69296458b' 
  AND token = '31m7+Lc9FdyigYY3gOaK29dLJ6prxorCDWPEO2IXtCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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