SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc3b61c1cf1e84a0928d2c919c0697469e1ead83016b7966adeb2adea1de5b8b' 
  AND token = 'vMM6lH/LXz3URPvc1zLkPyq3JpYFaZnueTTL7iaSxa0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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