SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e02f8c80bb1aee09eb79249547ebad2cdd8a9acfee9e5d046ad5f74df25ad88' 
  AND token = 'FSj/UGPmT2dWEmTGinX0nku+JgErgNFsDL9qAN9bPh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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