SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5519bc079904f709a9809c4f6296829336130945b3bcfcc4a6f52edccf5799d9' 
  AND token = 'lYsEUNNtgAiigLFZwCEH9Rr4HZ0KdkT+7JaZr1fd+Ps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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