SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '356594b4601343a5c0715b106bb5485bcd1f9ff62d1ef3b460e3706a66ca3460' 
  AND token = 'hl1B4AlMAvw2cZpVBzIs6eHJohha5pgj30YbfFgGJRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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