SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b270c71152c2672c409f8dd75b1ec520bd17132da2b0c28a3f827c5395089e8f' 
  AND token = 'lgC6CKyDqD6ap04A26KYIo6nHiWSQpnAxPRHxbpbjOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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