SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9a61a50e0b82c82bd8f668dc6619eb4238b1a1b0a2669639fb03b502118c267' 
  AND token = 'U4Kg6M2bvI02iA2S+xDqJNOMNvljr6EagaQb+hwVPGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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