SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcb6989d948e069ccd2eeb351708d472e1bca7c311c6f17e86add3ec3e6fcfee' 
  AND token = 'VYYPzjjEwJw3jW/10sBLpRaQ1CYjiDOjDvUUcfJBWFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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