SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74691d14a7e14fc7f34156d5361ce6c28887a8848fcc133a9511ded2396bac64' 
  AND token = '18qMr5wEFTq99wvb5/AaZkSZsxznbwHe82aY7roYlCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}