SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c9bf93f40297fb8e850e22f226a819d50d23cfc97476fcafc6018db2fb750c3' 
  AND token = 'OBawvzWIIBnwFg9DPK0rUDjWKVrdIUsfSMpF3CUZYPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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