SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8681a694237385cd6668b0e16a3fb6cc54997c845d9ec37d728873608d44c63c' 
  AND token = '1dCIV9sNOXY3jOJb1ro7AChnXc3D70lG3HCMRFe1B5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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