SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f683d08174372016c4d11f9bfa44a70a6f99766399ca1aae657019a85bfec93' 
  AND token = 'X814n+9zeJiRwS/lstoeiw5bYWFRBq7Q1MeTwuftB/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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