SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a588009057d070ef5a0b5a930f44ce09ef1d1ea0d7294abaf9ed7de258ce2496' 
  AND token = 'dTv2gjoa/S4CfdJKeWCd/EZaAJ55angZJdjZR0M/Emk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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