SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14c1e405f13497efb4d8b6255318f85821ad8665f739112a1bb0febeb2372a8c' 
  AND token = 'TQ+Ya7/NgAtuIzdyLhvqFu5+rje3AAsGWQjSdrNUI2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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