SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a648ebb4d230a487db4be5c96194584bba97385c31110dd857572240d5f12460' 
  AND token = 'Kh0dcM/5EjHZZ040O1w+2nbKyMuJoFiFKGsuTorhzWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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