SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'facab1b79d15f813c23b3259378c4e1232647b03a7a6471bef7ac1e65f7cf7cc' 
  AND token = 'mqvtjtXQWvi+nQ8Aj6s4Bx+KsgZaEmBMpFpdlxmrJvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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