SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6fe26ad8dbc75797ff5255609987dd10f30628bee862c38566343902ee2c0d' 
  AND token = 'C59kt9BUiKi18TPCrN1UAgHn5aiwaTNE9gLxWMFqXtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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