SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cffd9be397aead804a0bd9bcf5ebd713d151546b823f2885c8d2265fceccdb7' 
  AND token = 'MJ67rJcYQS/rRjYFein5+5rbUeBxIzvZpqLuBYtjbjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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