SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7597c77849c9e7d20ad9bea8000d247043395e4d525a4e9d78007dba77355c07' 
  AND token = 'XAQhoD+zRR3P4+f9dfC+nwRfcMmYZEzZKypZQX+vLvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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