SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47884c9654e0b3e17b9a21944fca8d274802ecfbca1a972eedcef9f85cd3c384' 
  AND token = 'EAJHqaPdTcYYzLwQBMnAe7hTa7FtkiRsQmrKpRj56kc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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