SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f58b5fb712504f8f6a8513fa1f9574706a2420b83608b63e2eaa45d774e69ac4' 
  AND token = 'QXjKVnSWARoHTrbCDb5TByYqkjR/5CqBkRFRY9fRP3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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