SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d27c3b746d8719fbc4b27946361045e908c30524ba927b1908c201a100b9813' 
  AND token = 'SQgbNu6PX2T9UZtyyVZrtoa1eB272aaumGxkqIUQJaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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