SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '000157b9f93ea2c91916be322afb7b4f465247bd9f62c4e1dc6317abaccfcc42' 
  AND token = 'TFmLiTBrjji9I4AGKDXJaQqdFRx0cSK6/E0Nllh6UaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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