SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9906b97d9061e6e738549f4f154421d5ef010b8493938bfae947ec678453c2a5' 
  AND token = 'YckXnOx0n8++niSyEBqNq3pKAGHYr69C1p91nmB9Ybo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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