SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '288b3173c0dd468da56c8e4a6e078ae932cda38a569ce2cb146f513ab953c20e' 
  AND token = 'pmQHycyOxwEwvy70FUfylnkDLTuEGcQLjuAXUZxHvbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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