SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ad0efcdf3c02c59143cdcbe7de42f64049060e2e2b684b4bd7226e4cc0a27a3' 
  AND token = '00y7e7qd/EgUZGWy5DUlp5dfmWkJPZXK71jUeuzZjC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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