SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3853ed8744bf1f8b8a13de3838ec981717886e0f0b57d6de66efb3465357d093' 
  AND token = 'Z6hgM4PhqC2o9Ma8fBpADmzk5OKuo/GsiM7wAzxQ8jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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