SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4302b115e722062346e14f81d18cc248e2031a619e3a04a77224491ab81c1bab' 
  AND token = 'ErnzCr0q7e5dsBqWiJR9DyL/Hs1bA0RegQcSfUkTw/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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