SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea6cc0ed8151810e88604294bd3071ada05715ffcc722d60254143efe2be868d' 
  AND token = 'c+B0aHs9jeUDDJdW0De9cELnklRdULs0k2NL6YFpZy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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