SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98d486cc8bf9136184f896422564deaa6988886f5e19e31043d36c770c010caa' 
  AND token = 'Vlh5fg3NZCegNQiTIvNBDt4RZTXeguZV3Vsn1cYxI7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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