SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e463bdaf1908756b5d2d0236bc56b549e7dea85bebba530769d6e72eb9cd7d0' 
  AND token = 'E1Bm8NLvHsMOmhbCn03XmiS4Jp3LdJ3HiXf5gSMSK5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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