SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5fb03fc606a466fa58cb7907c2f7957a40799adda0d099b43a62cddc6d22259' 
  AND token = 'dwjbTDrKXmbmAOnVKV9iCBWlO+lynvmxWgHQ77jwGD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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