SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90bd2bd7a905f93ae3b538db23a995b2fd59061a007292e911e4b17955c5ff2b' 
  AND token = 'i+yeJdQys19t+E1OVryh0EIVncJcyIbk6iPDKno/L28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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