SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a979684555e431e64758c2e6019c26a3c2f9b7f5f50a1b25e89ad798bf6213b3' 
  AND token = 'TLkTwFgYmHT2abkwoKdZTwsvHX38b0304kEg6OIslEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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