SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2369454b389135c99646de68c1b92cac9cce08c3efc5ddff16086c430aef00f' 
  AND token = 'ClTashg94OlVQBJRTNcQhdjsdowKsVMrO/UYjhyRPVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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