SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e4b82a6005a94ede61669f522f91a571e98f48dda9dd7506a8e60b2c8b52cc6' 
  AND token = 'CL2qK8mj9o5w6gWYiMm3hA86VGUQ6Q8/OqugF+hObU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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