SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e5874a48c6487352d30a8d86f1c53302a0dd348aad8bbeeefdeb6ee525078b' 
  AND token = 'n+Cy1+zdzIE4NioFXHBgWGFv61H9EdyHaepoeiGAMgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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