SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f47bb65f8e71e97cb869ec11ce22d8d60a43eded5ec644bfae325860da2b4eed' 
  AND token = 'tKWtTB18lcqn5eBiW39X3ddlfyIfCxMFNrIkFUj6TUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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