SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '899b7b1751cb53e1468dd6656fde40d147de71c13c060f82370a034564d533e4' 
  AND token = 'iqNhEnYTsFOZrtCEAyFIcqf3/5/rOFEr07fcGG47buc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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