SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2d5010c70ef58125ca43ae048951cb75ad5b4d1cad0823ad84bf1a1a901ba9f' 
  AND token = 'LnLe5Rq17g2HCZQySycEdnmCCFt9987z1sOQRy63HsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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