SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bdf7816a9371127b6184406174e0429b2972c38d2739f70ef9631fe098fbaed' 
  AND token = 'oygzXB/KZnKVlV9Qh3IBC5ylGTZozAIQpI4vX9ZSwxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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