SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'df4a839ddb63dbd019c2dc6d742a2d30a4ec1069de9a85b9bcaf5f36d73e9dbf' 
  AND token = 'rqR0u7zXCEVb25WwxCWSovp0yfRrB2XvVS93Vytz8xI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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