SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db911005a6847ceadc316db15bd8ee0a9c2ab8e5fd22642f0f6bf694bb3788d6' 
  AND token = 'jvVrZ3eSBOQ62Zyp/gH22nfPRY3BwXvQ1p9bak4e8CQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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