SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '105b0355c7d4f143bfb38222fb06a3d065ae03f3d222a0854ea1b2ccf1f61517' 
  AND token = '1JQ2tyH0SpSsqwSPHWsVjDlT/jdcF6cYaafXhHFybAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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