SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8205ce4ce0a2cb6cbdf1d17224f525bde42bc5a421585392bc0f0984302b2af0' 
  AND token = 'Iqmdek/FoXaRJggxqNB1v8JmUaCaw7ZMgf0Ty2M1XeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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