SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b854b3a1bf149fce0308d6f8d318b2b06c05c4d75fb6da15d4e7e0d2635742cd' 
  AND token = '5KNXyzOvqkoeKyqoraNkSEjEYCG6DL6CS1RHuFnIKtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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