SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c174d26d9587e958dd6984a00b5a83dbd3dff5e9b90eefaba18445eb66becc2' 
  AND token = 'zubqFetMTmFjDThWqy237Cl9Ax3VW5D8nn4NrPfOHwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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