SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d9c1a6f798dc1cd34ff1c9c6fc9e51b600e481d2246e674a455cf043f87bb28' 
  AND token = 'htop4aFQCA1CMEJhhz76mZzw0ZxgLEUHqs51HKOfZPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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