SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a68a10f36c62f207d5094742d63eb3ee38b468b9f51a4666f03331e8834739' 
  AND token = 'TFHbQD37/gZ7BIVqpWMjfomLLWV0vFnjJLqFgHKSllk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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