SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e287a43a9280294b48ca72c39ae0899f8ff6a6fa769c943a850c8b4b0ffe6c' 
  AND token = '2f6CxMllyBEPWZAyNphiP/HtS9tOxMEymxP4a0OuVsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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