SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9f12956cb011fd6a2b8ebbefd5c65c5104bd747673698baca28ade5562272c2' 
  AND token = 'twqS+CUjHd1Az5hF8yN5FrGEY041WaZJxMQgutbJFVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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