SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e61fa468c82e454766769ce3326ce56e841b9e0aa7e3b238dd555941295acf3' 
  AND token = 'McJ/xPXFKMGWu1zDgFOuUMz3DriuCIvXRNOp51f6oJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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