SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb2617fbf7842d6f0645b61a44d7a1fd5bb60205aa06be55cc51a5265491e50e' 
  AND token = '1CHH7ji1PIx3tbreIE1enwVJGEW/cmYXSpD0HHv8qu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}