SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c18b2eecdcbe28ef0e167569d232b0264e5228fa1130721bda121c759c2d1ee6' 
  AND token = 'GFPrnSaTEE7cgmTI6nWm2sySigXpVIbty01kDdPjDKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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