SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c476a28b07e8dabec9783b209dc89e126d8f8a97d23c1d9ccf6515b2654e380' 
  AND token = 'KZFUtEjAVMupuYf5WMouIUo1hLGBhXShP4//rEcu4KY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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