SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e1cb394f95572b66b5fe1b4f7aa6bdaad0a667b1459aa65908255535141eef' 
  AND token = '1M0P0isDmi/NUqwesRzBXdLAErzplpGeaM6W9BoYdBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}