SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bac87ee301bb6cbda6360c6080c085273ea34eae90154c46911eb5a94c1f6c6' 
  AND token = '5Z5bCNFLktwJEotFgHLYhoOD6ylbeszJo96Uu6NEISU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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