SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '384b7d803e263ba24e982c1f682f9c270172985c48dfadd83e6b214315e9e032' 
  AND token = 'XL30iMfNfCDxhBIGFBwAZklXK1xGPYqiI3EWWDmGmJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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