SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dec6bb899f30cef945eff3699233dec9ed8ab64841465110d74aa86e4e93b742' 
  AND token = 'fy5c2OCaXNOGagW8dyYGYD4D8Q31eiYi4bSaBMrIPJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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