SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beda4478924060268175c5110480400e766493f940adceaaab9627605400804e' 
  AND token = 'TkL1yzrVY8pmgPJuC4OrK+hSotNz503dplSIv283xME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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