SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e84f58191fdd651ef49d6a5416940b0245bde0045442a8fa3bd796b16f35bf' 
  AND token = 'IefuEIv/YcF0uyavYrItS10+SPPBpjMlQy+XQovutfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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