SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dac21ecc5c9e90fb077fc676cd7bc724501f306a8a505b7b57a38c897c77566' 
  AND token = 'q4bfTdXULZIZBqrGlIURKeuMAO1p5jbd9CEEGNRHIGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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