SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aef1b149536ed8f7874480156f21fdce78ec501db9d0229919ef04dc9a56dfe6' 
  AND token = 'fXBRlQ5CNhX/u4pwPyoFqDTiVg+ODMRxKdY6Z2qZerQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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