SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3aa573e79930b31406d17dee622901009ec59f9c3787ed756980487ff120e36' 
  AND token = 'JsBsL/ItKGxEMuD+hn6hGMUEHohvoZWKuC5zHVCZ2Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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