SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd90dd04446157d4addb29d17a5c17ba6f12ede838fe1d248843f8cb4179d82e4' 
  AND token = 'uGY6ojbInp/6tm0B8qIlWyg+pUyr9R2hffQqw2GJVes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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