SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e31e380aad1c93fa0286bc1c0cf893415dc345b0519184b3bc315a7d922ca871' 
  AND token = 'n1S6FsTA02Fm3uWtvSZKi8seVQT1aHPbdC0a1+m8liw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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