SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7340ddbd58ab972f7ed506629fb6a181b8fe27faa45d62bae44e92a266548268' 
  AND token = 'GHp85jJGUY/0/ZHzQ+1T5IziPlmgC3k4v8NkpAFVryk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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