SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1221993cf1322acddffc1ce4760b165953dc089cbff747ee596a4fd3e599ed75' 
  AND token = 'iu6EjA7GEqK19iWOBRvBxsNv+KvKvCCEEP5+/jOWIJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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