SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cdd949b0e22d51125590383a974f8659ba04fce8ef6a2a01a4789aadfb656e3' 
  AND token = 'TonJ3dPgtacAEea0tqjoRw3ePYkue2Yfmo1UTmWPYcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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