SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29a2cd51d8e974f602aa3e8cbb69746fcfd0ff7b9f297ab8f1360bfbc82ddca0' 
  AND token = 'iMlECewV5MqyKRVmn913f0b+/RVs1jf57DuuTtZ2rY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}