SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfbd5a13ebb6112efbaa98b4be4bd79140964af19fef03ea752a975800a7114b' 
  AND token = 'qq+3wEPA+ktvXWjJEr4fNagiCIQMjIIUqZvgybbsuew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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