SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac0439b0669b4009e173ce68628cfaadbf2ceb163a0b9e2bbf525f842fbac2d7' 
  AND token = 'WxpzAcXbTcNFYbsLrVJ2hw0mVghklKXJf13E1EW/wh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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