SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37252284b4db4254e7c720cb3cb727133e7a171129bed52d02e014ab4929845f' 
  AND token = 'rPlxFHQFClTLlyhakKZsxkYyHI/oKk54mulWRzQQZAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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