SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c15f1e6f49d67b67ca28a206144838e66064849c3b10b507e78e8dcdc689fac' 
  AND token = '9k+u2wZhZMEnRx4HIXjfYzUzXxy8YU4n0FvZUPJPPrM=' 
  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"
    }
  }
}