SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3df990452a036c7089e2747f9b12852b45a027d4d6d247fa43b86f3c8e296f37' 
  AND token = 'o+1EOKHiMjeFzUnqJ+jlYUudAkdaeBhAlxQltYuLfRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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