SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd46f6fd0b0bb402bb71a7d66c0ecafcdec8dc9702cf30237fa95e7e535ff53' 
  AND token = 'LX+chcKUC90E5glwZ4gzRFfuXmWtJ/isoQ2rtVhPErE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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