SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b856976c258269880fe89972958183d47d8597e152958d1d7f7ab73530be4cf' 
  AND token = 'WIrYboUaNzNlAF2DA/vrKR7tPG+d7ygdtU4hQTa938U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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