SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43624fd0cf3e58f8d2618b2700f2321fed96bb8f093383679612488af56b11f0' 
  AND token = 'DyS8j7ZczIL8rfs/tB/Yk4ea7tVFjO9pKU+s7QvZnag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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