SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61250e67ad0dad0ba2b9af05e2a236e354cae95307df4ea2fa620914b8fc130' 
  AND token = 'Q9vHAW3S3+Oxl6GkkzRG5cZvSYXmAsZJhLKphMuug8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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