SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72b4e44a90be5969541a2c343cecb36f9a5e5185028f83f05f027516e0d0e6e1' 
  AND token = 'nOrAL6BDqkfFx3EyFMDFYr/rhDoUvJvoUa7RZ5LituA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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