SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9aa9005a3ccf976df656389462eeffa4c1b9cb628dc39e9f7206358fb70dadc' 
  AND token = '5mkMpc0tPwBz/HSaAo439xBr+VBuFUZVrTUBk5GHwhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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