SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae819734c73e17996848d718049879fc112be44f7a4466b2c24dac60d2c71c79' 
  AND token = 'tmyH1EvR1n4eniWp3jYSCVWqFQDawPdT9HiW5M6N2u4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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